I've never tried this, but those numbers are interesting and raise some
questions for me, especially the UW/DW relationship, where the UW is reduced
by almost as much as the DW. Would you ascribe the effect strictly to spring
action when the front of the punching is first compressed and then released?
If so, how much difference would thick vs. thin punchings make? How much of
the weight difference (in the case of the original whole punching) goes away
as the punchings are compressed in front through use? (if it changes much at
all, leveling the keys and replacing the punchings in a different
orientation would seem to produce random key-weight changes). Would the
effect be mitigated by beveling the balance rail at the point where the pin
enters the rail (ignoring for the moment the problem of likewise beveling
the rail under the sharps)? These all would seem to be random variables in
the key-weight equation that I've never considered before and make me wonder
if some of the weigh-offs that I've done could have been avoided.
On a related note, has anyone retrofitted a standard keyboard with S&S
bearings? How much difference did it make and how much trouble was it?
Thanks in advance to anyone who can answer any of these.
Kerry Kean
www.ohiopianotuner.com <http://www.ohiopianotuner.com/>
_____
From: Mark Dierauf [mailto:pianotech at nhpianos.com]
Sent: Friday, January 08, 2010 11:37 AM
To: pianotech at ptg.org
Subject: Re: [pianotech] PUNCHING TRICK ???
I seem to consistently get more like 5 grams from the half punching trick
(that is, tacking the punchings to the keys with a drop of glue just behind
the balance hole and slicing them in half at the hole when the glue has
dried. Here are the before and after numbers from an S&S B action I
currently have on the bench. As can be seen in the bottom row, I've saved
and average of 6.1 grams of downweight and nearly 6 grams of balance weight.
This piano had new Renner parts installed probably 40 years ago and has
always been a beast to play. I'm storing it long term and am just trying to
make it more playable without spending any more of my uncompensated time
than possible. SW's are all over the place and FW's are near maximum values.
Before
After
Note
DW
UW
BW
DW
UW
BW
1
57
32
44.5
52
27
39.5
2
62
32
47
55
26
40.5
9
59
30
44.5
52
24
38
10
60
33
46.5
51
25
38
16
61
32
46.5
57
25
41
17
64
35
49.5
53
28
40.5
20
55
29
42
50
25
37.5
21
64
41
52.5
57
34
45.5
28
64
38
51
59
34
46.5
29
67
45
56
60
39
49.5
40
52
31
41.5
49
25
37
41
64
39
51.5
58
33
45.5
52
55
35
45
50
30
40
53
53
32
42.5
47
28
37.5
64
43
28
35.5
39
24
31.5
65
42
24
33
35
20
27.5
76
53
33
43
47
29
38
77
50
29
39.5
42
24
33
87
52
32
42
47
27
37
88
55
34
44.5
50
30
40
Averages
56.6
33.2
44.9
50.5
27.85
39.175
- Mark
Barbara Richmond wrote:
Hi Jack,
I guess the need would be to make more than 1 gram of difference in the
touch. ;-)
Barbara Richmond, RPT
near Peoria, Illinois
----- Original Message -----
From: JWyatt1492 at aol.com
To: pianotech at ptg.org
Sent: Thursday, January 7, 2010 4:53:50 PM GMT -06:00 US/Canada Central
Subject: [pianotech] PUNCHING TRICK ???
Hello to All.
For the last 50 or so years the punching "Trick"
has been called " Clipping the Centers ".
It is not necessary to do any gluing. You clip
the center rail felt just a little in front of the center
pin hole then replace the punching, clipped side
forward.
It is generally thought this will make about one
gram difference (lighter) give or take. I use my
center pin cutter to do this procedure.
If you can understand the principal of a see-saw
then you understand the principal of a lever.
The Herz- Erard action is a group of levers working
with each other. Five ( 5 ) to be exact. Not 50
just five. Its really " not " that hard to figure out
how to change touch knowing the key depth and the
hammer blow distance.
You lighten the load, change the fulcrum or reduce
friction. Maybe one, two or some of all three. You
do not have to make things complicated unless you
have " the need ".
Jack Wyatt
Dallas,
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